1. Field of the Invention
The present invention relates to a navigation apparatus for enabling mainly an external server or the like to search for a route up to a destination, and a route distribution server for use as such an external serve
2. Description of the Related Art
Some known navigation apparatus for use on motor vehicles enable mainly an external information center to search for a route up to a destination (see, for example, Japanese Patent No. 3368775).
According to Japanese Patent No. 3368775, after sending information as to the present location of a motor vehicle and its destination to an external information center, the navigation apparatus performs route guidance using a tentative route found by a route setting means {navigation ECU (30)} of the navigation apparatus until it receives a route based on the sent information from the external information center (see, for example, FIG. 4 and paragraphs [0012], [0036] of Japanese Patent No. 3368775.
According to Japanese Patent No. 3368775, the route setting means {navigation ECU (30)} calculates a route cost according to the Dijkstra's algorithm based on link information and connection information, and sets a tentative route as a shortest route from the present position to the destination (see, for example, paragraphs [0012], [0036] of Japanese Patent No. 3368775). According to Japanese Patent No. 3368775, the navigation apparatus uses only one condition for searching for a tentative route. Therefore, it may possibly perform route guidance not intended by the user in the process of seeking a tentative route. For example, according to Japanese Patent No. 3368775, even when the user does not want to use a toll road such as an expressway or the like, if a toll road is included in a shortest route, then the navigation apparatus presents a route in which the user needs to use the toll road.